1. Field of the Invention
The present invention relates to a process for controlling the braking force or driving force as a wheel longitudinal force in a vehicle in which longitudinal forces applied to a plurality of wheels can be controlled at least on a front wheel side and on a rear wheel side.
2. Description of the Related Art
There is a process in which the braking force as the wheel longitudinal force can be controlled at least on the front wheel side and on the rear wheel side, and which is conventionally known, for example, from Japanese Patent Application Laid-open No. 237252/89.
In the above prior art process, the braking forces for the left and right front wheels are controlled collectively, and the braking forces for the left and right rear wheels are controlled independently. When the frictional coefficient of a travel road surface is different on the left and right sides of the vehicle, when the carried load variation is large, as well as when there is a difference in capacity among tires of four wheels (for example, when studless tires are mounted on only driving wheels, when one of left and right wheels is failed to be braked, or when a temper tire is mounted on a certain wheel), an anti-lock control (which will be referred to as an ABS control hereinafter) of any wheel liable to slip is started during braking and at this time point, a driver of the vehicle feels that the ABS control is executed. Therefore, even if a margin is left in the braking force for other wheels, the drive cannot further depress a brake pedal in many cases, and cannot obtain a maximum braking capacity for each wheel.